1. Field of the Invention
This invention relates to an agricultural row marking apparatus of the type that makes impressions in the earth to assist in the placement of seeds or seedlings during planting.
2. Description of the Prior Art
Row markers, furrowing tools, and earth impressors in general are well known in the art. One of the more conventional types of row indicators is a spring tooth marker comprising one or more vertically mounted metal tines, each of which etches a linear furrow when pulled through the field. A combination garden marker and furrow opener is disclosed by L. H. Wells in U.S. Pat. No. 4,020,906. This device comprises an enclosed water-fillable drum which is rotatably mounted to a yoke and handle. A V-shaped projecting flange fastened to the outer cylindrical drum wall impresses a planting groove in the soil parallel to the direction of travel.
In U.S. Pat. No. 2,146,222, Pace teaches a cotton seed planter opener comprising a ground wheel having a flange around its outer edge to produce a seed furrow of longitudinally continuous wavelike form. A similar device is taught in U.S. Pat. No. 107,074 to McConaughy, wherein a cylindrical field roller is fitted with flanged rims or toothed rings for cutting a plurality of parallel seed furrows in the ground. Another rotary furrowing tool is shown by Hill in U.S. Pat. No. 3,710,871. It differs from that of McConaughy in that it cuts a single continuous seed furrow by rotating a cylindrical rim equipped with alternating cutting blades and dig-out teeth at a circumferential velocity greater than the linear velocity of the drive frame.
U.S. Pat. No. 419,892 granted to Schumacher and U.S. Pat. No. 2,228,265 to Garey show variations in cylindrical land rollers fitted with triangular projections for packing depressions or basins into the soil to collect water and prevent erosion.
While the above-mentioned devices are suitably designed for their disclosed functions, none can advantageously be used for simultaneously marking precisely spaced seed rows perpendicular to the direction of travel, and row divider marks parallel to the direction of travel and perpendicular to the seed rows. In laying out test plots and nurseries, it is frequently desired that the seed rows be equidistantly spaced and that these seed rows are divided into two or three short sections. The seed from a particular cultivar or experimental cross can be planted in each section. A method of accomplishing this with one of the existing monodirectional markers is to make a first pass in the direction desired for the seed rows. Then the marker is lifted from the soil or removed from the tractor and a second pass is made in a direction perpendicular to the first, by driving the tractor wheel-on-wheel track. The area between the wheel tracks or imprints is commonly designated as a "range". Imprints parallel to the direction of travel and dividing the seed rows into two or three sections within the range can be made by a separate marking tool if so desired on the second pass. Disadvantages of this technique are that it is time consuming for the operator and delays the work of the planting crew until the second pass is complete.